Downer Oneesan wa Asobitai

Haru Nitta has just entered junior high and is confused by the changes around him. That is when he is approached by a mysterious older sister one evening on a park bench. "Come on, boy. Choose your Bey." Bey... Bey? Beyblade?! The older sister's true identity is that of an active CoroCoro Comic reader who loves toys and games more than anything else in the world! A full-fledged hobby comedy featuring a gloomy older sister who calls him "boy" and whose attitude matches the setting sun perfectly! (Source: Shogakukan, translated)